There are many different methods in the state of the art for the billing of calls, i.e. for debiting a monetary amount for a call of the customer carried out. Calls may be billed based on duration and destination number, for instance. Thus calls to foreign countries during business hours may be billed at a higher fee than calls within a city network outside of business hours, for example. Such billing models may be supported by offer concept and demand for services. The billing of calls may also be based on a flat-rate fee, so that a call is always billed at the same price. A flat-rate fee can bring savings during operation of the technical installations necessary for the billing. Implementation of a location-dependent billing of calls for mobile telephones is also known in the state of the art, in particular during a change of location between different network operators (roaming). Network operators of mobile radio networks would also like to apply fee structures by means of which fixed network telephony may be competed with directly, for example. To this end, the network operator of a mobile radio network would use an appropriate fee for the billing corresponding to the current location of the mobile telephone. The current location may thereby relate to the place of residence of the user, to the means of transportation of the user, such as a train, or to the location in an office building. For the location at the place of residence of the user, the network operator of the mobile radio network would apply a fee structure for private telephone connections that competes with the fee structure of the network operator of a fixed telephone network. Correspondingly, the network operator of the mobile radio network would apply a fee for the billing of calls for a mobile location such as, for example, in a train or on the street, or for a location in an office building by means of which the respective network operator would be able to compete directly at these locations.
Described in the international application WO 99/05875 from the Assignee Siemens AG is a method for the billing of calls. Zones are defined for a subscriber through a combination of radio cells and/or areas of location. Such zones can relate to a home zone, a city zone or an office zone. A zone tariff is assigned to a zone, and a billing device is informed about the zones defined for the subscriber, which are used for determining the call fee when the subscriber is located in one of the zones.
Described in European patent application EP 0 939 570 from the Assignee Siemens AG is a method for location-dependent billing of connections between mobile subscribers. With a connection of a mobile subscriber, location information is determined for the radio technical installation in connection with the mobile subscriber, and a home local area rate is billed if the location information pertains to a home range for the subscriber.
A drawback of this method is that such ranges or such local information may be determined with too little precision for many applications, or the current location of a user may be established in an insufficiently exact way. Also a disadvantage of this method is that the technical implementation is too costly.
Described in the U.S. Patent Application with the Publication Number US 2003/0054836 is a method of time recording of a person in motion. By means of a reading device, data is read by a transponder, and is transmitted to a mobile telephone. By means of the mobile telephone, the data is transmitted to a control center, time information being stored in the control center.
Described in the international application WO 98/58509 is a chipcard for GSM cellular telephones. The chipcard comprises storage means for storing identification data for a subscriber as well as electrical contacts for connection of the chipcard to a mobile communication station. The chipcard contains at least one coil that enables the setting up of communication between the chipcard and a communication station located outside the external device.
Described in the international application WO 2004/054304 is a method for anonymous tracking of the position of a portable device in a wireless infrastructure. By means of the wireless stations, a unique identifier of a device is registered, for instance via the ZigBee protocol. The identifier is stored in a database via a backbone of the wireless infrastructure together with a piece of time information, so that the last interaction of the device with a station may be checked.